2002 QX4 idle knock

[buzzdriver]

Hi everyone, my first post!
Recently bought a QX4, 166000 kms, runs strong and clean but has a intermittent knock when idling, warm and out of gear. It seems to disappear when put into drive or reverse. Sounds like an engine knock and hoping it is something not too serious. Changed oil a couple of times 10W30, doesn't leak, oil looks and smells fine. Maybe a belt or idler or mount or ?????
Thanks.

[Infinitiguy19]

Any Check Engine Light Codes?

[fleurys]

Engine knock on idle on these engines is very likely to be the power valve screws that fell down in the cylinder... usually not good news.... I would suggest strongly to read this post threadlocker-on-power-valve-screws-pics-t304263.html and take the time to see if they are all there... This procedure will not be useless cause if they are all there, you really want to loc-tite them to prevent this engine killer.... If some are missing you will know what caused it... you need to start there first...no way around it...

[buzzdriver]

Any Check Engine Light Codes?

No engine codes, lights or anything. Mileage is about average for 3.5 and engine starts fine and runs pretty good.
Engine kinda sounds like a sewing machine when running but heard that is the way they sound.
Power valves sound like they should be looked at and loc'ed up to prevent future disaster.
Cheers

[buzzdriver]

Engine knock on idle on these engines is very likely to be the power valve screws that fell down in the cylinder... usually not good news.... I would suggest strongly to read this post threadlocker-on-power-valve-screws-pics-t304263.html and take the time to see if they are all there... This procedure will not be useless cause if they are all there, you really want to loc-tite them to prevent this engine killer.... If some are missing you will know what caused it... you need to start there first...no way around it...

Thanks for the link. I went through it and looks like I'll be checking out those screws. If one made its way to innards, wouldn't it stop the engine in a hurry?
Will be going through everything. I've heard a bad belt or idler can sometimes make odd noises. My QX4s' belts will often screech when starting engine. I guess belts are in order.
Cheers
Rob

[fleurys]

It would not stop it... I have read a post on another forum from a member when it actually happened.. He heard a loud crunching noise , like metal being hit in the engine for about 10 seconds then nothing.. The engine never stopped, then he could hear clicking noise on idle and no noise when he was revving it....

In any case, if one or more screws made it's way to your cylinder, then they are probably lodged in your catalytic converter. I think they are bronze or copper screws, so they are softer metals. You may want to make sure to monitor closely your oil level consumption. If your truck does not take any oil then it is safe to assume your rings are ok and the cylinder walls are not damaged... At that point the noise would probably be a valve that has bent just a bit...

in any case, you need to check these damned screws.:-).. The 3.5 engine is really a good engine, but this is probably the only really bad thing about it... I hope for you all your screws are there...then you know it's another problem and probably a smaller one..

[buzzdriver]

Just recently brought my QX into dealer for knocking sound. They suspect it is a loose torque converter and believe they can get at the bolts through the starter. Sounds about right as it is only when hot, in park or neutral. I'll go with this "$$$ three hour tour" and see if they can fix it otherwise a 10-12 hour job yanking the transmission if they can't get at the bolts through the starter "hole".
I'll let you know the outcome is this weekend.
Cheers

[buzzdriver]

No answer as to what the problem knock is only an "internal engine noise". I kinda know that already. I did however get a $400 bill to tighten torque converter bolts for no reason, greasy seatbelt/door panel and car wash!!
I'll avoid dealer forever.
Where can I get a full service manual?

[fleurys]

We all learn.... Sorry to hear that the stealers could not find anything....

I was not able to find a 2002 fsm but did find the 2001... should be the same powertrain etc... not much changed I think...

http://www.nicoclub.com/FSM/QX4/2001%20QX4/

S.

[buzzdriver]

Thanks for the link, looks impressive with lots of stuff to keep me busy.
Cheers from
Victoria, British Columbia